Stingray injuries are usually reported from coastal regions. The injury is caused by the tail spine of the stingray, which can penetrate deep into the soft tissues, and the venom in the tail can cause extensive tissue damage. Imaging plays a very important role in patients with stingray injuries, especially to detect the presence of retained foreign bodies and its complications. We present three cases of stingray injuries to the extremities, with a special emphasis on radiographic findings. Embedded foreign bodies that were radiographically visualized were removed in two of the patients (one patient was discharged at request and was lost to follow-up). We also discuss the types of injuries, clinical presentation, importance of imaging and management considerations in stingray injuries.

How to cite this article:
Srinivasan S, Bosco J, Lohan R. Marine stingray injuries to the extremities: Series of three cases with emphasis on imaging.J Postgrad Med 2013;59:309-311

Stingray injuries to humans are reported from various parts of the world, especially from the costal regions. The clinical features and management of stingray injuries have been discussed in the medical literature. Imaging plays a very important role in patients with stingray injuries, but is often understated. Radiograph and ultrasound are useful modalities to detect embedded foreign bodies in patients with stingray injuries to the extremities. We present case reports of three patients who had injuries to the extremities by marine stingray, with emphasis on their radiographic findings.

Case Reports

Case 1

A 38-year-old man, employed as a cook in a barbeque shop in Singapore, presented to the emergency department with a history of sting by a stingray in his index finger few hours before presentation. A 7-cm foreign body was still present. The finger was inflamed, swollen and tender. Vascularity was intact. Radiographs showed the tail spine (stinger) of the stingray penetrating deep into the index finger and in close proximity to the bone [Figure 1]a, b and c. The finger was cleansed with soap solution. Under aseptic precautions, the stinger was carefully removed under local anesthesia. Hemostasis was achieved and the patient was started on a course of oral antibiotics (Cephalexin 500 mg three-times daily for 2 weeks). The patient was discharged next day. On follow-up, the healing was good and the patient did not have any complications.{Figure 1}

Case 2

A 40-year-old man presented to the emergency department 10 days after being stung by a stingray while he was swimming in shallow sea water in the eastern part of Singapore. He had a puncture wound and swelling in his right ankle, and there was serous discharge from the wound. He had taken initial treatment with a local general practitioner and was prescribed oral Augmentin (Amoxycillin and Clavulanate - 625 mg three-times daily for 1 week). Injection Tetanus toxoid had been given. Presently, during his visit to the emergency department, radiograph [Figure 2] a and b] of the ankle showed a small sharp linear foreign body behind the medial malleolus, deep within the soft tissues (likely representing the barb of the spine). The patient was initially started on intravenous Augmentin (Amoxycillin and Clavulanate) and later, based on the culture of the fluid (which grew Shewanella), intravenous ceftazidime 1g three times daily was started. The wound was cleansed with soap solution and chlorhexidine. Under aseptic precautions, fluoroscopic removal was attempted twice to locate the foreign body after local anesthesia [Figure 2]c. However, it was not successful. The patient was discharged at his request and was lost to follow-up.{Figure 2}

Case 3

A 22-year-old man presented to the emergency department with a history of sting by stingray in the right foot while swimming in shallow sea water in the northern part of Singapore. He presented 3 days after the injury with progressive swelling and persistent pain. Intramuscular injection of tetanus toxoid was given. Radiograph of the foot showed a sharp, linear foreign body (barb of the spine) in the deep soft tissues adjacent to the medial cuneiform [Figure 3]. Incision and debridement had to be done as there was necrosis of the subcutaneous tissue and the foreign body was present in the muscular plane. Intravenous antibiotics (Cefriaxone 1g twice daily) were also administered and the patient was discharged after 2 days. Oral Cephalexin tablets (500 mg TID) were prescribed for 2 weeks.{Figure 3}

Discussion

Stingrays are cartilaginous fish seen in salt and fresh water, varying in size from 10 inches to 12 feet, taxonomically belonging to the class Chondrichthyes (subclass Elasmobranchii), forming part of one of the largest group of venomous marine animals. [1],[2] They are generally known to use their sting in the tail for self-defense, but have gained notoriety because of human attacks, when provoked. Such injuries are common in fishermen, aquarists and divers. A commonly described situation is accidental stepping by such people over the rays of these flattened creatures, which lay well camouflaged in shallow waters, partly buried in the sand, and results in injuries in the distal lower extremities. Fishermen are prone to upper limb injuries when they attempt to disentangle from fishing nets. [3] Up to 1500 cases are reported each year in the USA, with few fatal events. [3]

Most injuries are caused due to the tail of the stingray. The tail is a unique venom apparatus composed of its caudal appendage, spine that is made of strong bone-like cartilaginous material called vasodentin, small backward projections called barbs, its enveloping integumentary sheath and associated venom glands. [3] The venom usually contains toxic enzymes such as 5-nucleotidase and phosphodiesterase. The spine and the ventral glandular tissue are sheathed in an integument that tears open when the spine is plunged into a victim, causing an instantaneous release of venom. Pieces of distal spine or stinger or barbs and venom secreting may remain unrecognized in the deeper tissues and can cause prolonged toxic effects. [3] When envenomation occurs, a unique inflammatory cell infiltrate, composed mainly of lymphoid cells, CD3+ and CD4+ lymphocytes, and eosinophils is seen, responsible for the distinct pattern of acute inflammation. [4],[5] Complications such as abscess, delayed healing, tissue necrosis, gangrene, osteomyelitis, necrotizing fasciitis and septicemia can occur. [5]

Thoraco-abdominal stingray spine injuries are rare, but can be fatal due to arrhythmias, cardiac tamponade, aneurysms, major vascular injuries and arteriovenous fistulae. The cardiac complications are partly contributed by the cardiotoxicity of the venom. [6] A sensational case of death was that of the famous Australian naturalist Steve Irwin on 4 September 2006 by a penetrating stingray injury to the heart while filming off the Great Barrier Reef.

Imaging plays an important role in the evaluation of stingray injuries. [7],[8] Routine radiographic evaluation is mandatory in all the cases of stingray injuries of the extremities, mainly to rule out radiopaque foreign bodies as well as to rule out the presence of gas in the soft tissues, which may be due to secondary bacterial infection of the wound. The barbs and the stinger are usually radiopaque and are seen in radiographs. [3],[7],[8],[9] In all our cases, radiographs were extremely useful. In the first case, radiographs were useful to assess the depth of the penetration of the foreign body and also to rule out any bony injuries. In the second and third cases, the radiographs showed the retained foreign body and hence were helpful in further management. However, sometimes, the cartilaginous parts are not radiopaque [10] and hence ultrasonography (US) is needed in such cases. US may also be used in removal of the foreign body in cases where fluoroscopy guidance is difficult, as in our patient. [3],[7] Computed tomography (CT) may be necessary in visceral injuries such as the eye and in injuries of the thorax/abdomen, not only to visualize the foreign bodies but also to assess the severity and extent of the injuries. Intravenous contrast will be usually necessary. Magnetic resonance (MR) imaging is useful in cases of deep soft tissue infection, necrotizing fasciitis or myositis, and to rule out osteomyelitis.

The management depends on the site of injury. Injury to the face, thorax or abdomen requires emergent imaging, critical care monitoring and surgical management. In patients with stingray injuries to the extremities, thorough washing is performed. Only superficially located spines or stinger can be removed immediately at the site of the injury.

The management of injuries of the extremities can be classified into medical and surgical components. There are strong evidences suggesting that immersion in warm water is said to be an effective therapy [10],[11] that helps to deactivate the venom as well as to reduce the pain. However, there are reports that criticize the use of warm water therapy, especially after local anesthesia. [12] Warm water therapy is usually given as a first aid measure, and it is not a definitive therapy. None of our patients had warm water immersion as part of management. Other important components of medical management include antibiotic prophylaxis, analgesics and local anesthesia. In our cases, the cephalosporin group of antibiotics was very effective. In our second patient, the culture of the discharging fluid grew Shewanella that was sensitive to cephalosporin (Ceftazidime). Surgical exploration and debridement is the most important part of management. [3] Debridement was needed in our third patient as there was necrosis of the subcutaneous plane. Necrosis may worsen even after initial debridement and careful reexploration may be necessary. In patients with progressive necrosis, hyperbaric oxygen has been tried successfully to promote healing. [13] However, its role is controversial. [3]

We conclude that imaging plays an important role in stingray injuries and it is necessary for the radiologists and the treating physicians, especially in the coastal regions, to be aware of the nature of stingray injuries and potential complications and to understand the role of imaging.